Shifts in the macroeconomic environment can have a significant impact on audit work in terms of complexity and quantity. Higher complexity and risk are sometimes accompanied by increased risk of default or audit effort, which we would expect to be reflected in audit fees. Earlier studies on the impact of external factors on fees, mostly focused on specific events and concentrate less on the development over a longer observation period. The purpose of this study is to complement the literature by observing the audit fees of Swiss companies and to assess the impact of macroeconomic influences.

The sample was formed on the basis of conditions. The companies must belong to the SPI, apply Swiss GAAP FER continuously from 2013 to 2021 and have conducted their IPO before 2013. The reasons for this are the establishment of the same regulatory environment and thus ensure comparability, to include companies from different sectors. The sample includes 41 firms. Descriptive analyses and a multiple linear regression model as well as a mixed effects model are used to analyse the results.

The results of this study reveal that the variables “Number of Entities” and “Net Revenue” provide a high explanatory contribution with an adjusted R² of 0.908 to the development of audit fees. Real GDP and the growth rate of audit fees show a visible similarity. This is consistent with the finding of a 90% correlation at the uppermost level between total audit fees and nominal GDP. However, we did not find a statistically significant correlation between audit fees and nominal GDP at the firm level, which is partially attributable to the high explanatory contribution of the variables “Net Revenue” and “Number of Entities”. Furthermore, we observe a clear tendency for audit fees to drop after the change of auditor. However, with an overall decrease in audit fees of 16.84% after all auditor changes of the sample companies within the observation period, this is significantly less than found by previous researchers whose result of analysing other samples was about a 25% decline. In both matters our findings are coherent with existing literature. This study provides a forecast model of the audit fees for each of the observed firms.